Question

我想创建一个考试安排系统。现在我的目标是避免用户在SQL Server 2008中为同一个房间插入冲突时间表。例如：

房间 202 有

的时间表

02/27/2017 4:00pm - 5:00pm

那么如果房间 202 的用户输入是

，该怎么办？

02/27/2017 3:50pm - 5:10pm

显然这是冲突。

如果我要在两者之间使用，显然它不适用于给定的示例输入。

请帮助。感谢

Answer 1

就像尼克所说，between正是你所需要的。在这种情况下，与exists或not exists结合使用，您将能够避免计划冲突。只有当同一个房间的同一天没有条目进入时，才会执行insert，其开始或结束时间介于新时段之间（表示存在冲突）。

看看这个例子：

SQL Fiddle

MS SQL Server 2008架构设置：

CREATE TABLE schedule
    ([room] int, [date] date, [start] time, [finish] time)
;

INSERT INTO schedule
    ([room], [date], [start], [finish])
SELECT  202, '2017-02-26', '16:00', '17:00'
WHERE NOT EXISTS (SELECT * 
                  FROM schedule 
                  WHERE room = '202' AND date = '2017-02-26' AND 
                   (start BETWEEN '16:00' AND '17:00'
                    OR finish BETWEEN '16:00' AND '17:00'))
;

INSERT INTO schedule
    ([room], [date], [start], [finish])
SELECT  202, '2017-02-26', '15:50', '17:10'
WHERE NOT EXISTS (SELECT * 
                  FROM schedule 
                  WHERE room = '202' AND date = '2017-02-26' AND 
                   (start BETWEEN '15:50' AND '17:10'
                    OR finish BETWEEN '15:50' AND '17:10'))
;

INSERT INTO schedule
    ([room], [date], [start], [finish])
SELECT  202, '2017-02-26', '15:00', '15:59'
WHERE NOT EXISTS (SELECT * 
                  FROM schedule 
                  WHERE room = '202' AND date = '2017-02-26' AND
                   (start BETWEEN '15:00' AND '15:59'
                    OR finish BETWEEN '15:00' AND '15:59'))
;

查询1 ：

SELECT  *
FROM schedule

<强> Results ：

| room |       date |            start |           finish |
|------|------------|------------------|------------------|
|  202 | 2017-02-26 | 16:00:00.0000000 | 17:00:00.0000000 |
|  202 | 2017-02-26 | 15:00:00.0000000 | 15:59:00.0000000 |

在应用程序中，使其看起来像这样：

伪：

SELECT count(*)
FROM schedule 
WHERE room = '202' AND date = '2017-02-26' AND
      (start BETWEEN '15:00' AND '15:59'
       OR finish BETWEEN '15:00' AND '15:59')

if count(*) = 0 then
     INSERT INTO schedule
       ([room], [date], [start], [finish])
     SELECT  202, '2017-02-26', '15:00', '15:59'
else
    ERROR "CONFLICT WITH ANOTHER SCHEDULE"
end if

SQL调度系统

1 个答案: